European forests are of immense importance to people, the environment and the economy. They provide timber, biodiversity, water catchment protection, mushrooms, medicine, beauty, protection against avalanche, flooding and landslides and many other benefits. Some European forests are hot spots of biodiversity, such as those in the Mediterranean basin.

European forests, however, are under unprecedented threat from three factors:

Rapid climate change, which places ecosystems under stress. The dominant vegetation in the forests comprises many long-lived tree species. These trees have little ability to adapt to environmental changes occurring over the next few decades, making the forest ecosystem vulnerable.

Increased global trade, population mobility and tourism are leading to an escalation in the numbers of alien pests and pathogens intercepted at ports of entry to Europe. These interceptions are only a small proportion of the alien organisms arriving within the EU from other continents, and escapes into natural and plantation forest ecosystems are occurring.

Interactions between climate change and pests and pathogens (indigenous as well as alien) will have serious impacts on forest trees' susceptibility to attack. Permanent establishment of many alien pathogens and pests throughout Europe is likely to increase with climate change. A large number of novel, unprecedented forest health problems are likely to occur in the future